diff --git a/projects/vstudio/libpng/libpng.vcxproj b/projects/vstudio/libpng/libpng.vcxproj
index de7fc3c..9bfb718 100644
--- a/projects/vstudio/libpng/libpng.vcxproj
+++ b/projects/vstudio/libpng/libpng.vcxproj
@@ -84,7 +84,7 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <PrecompiledHeader>Use</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
@@ -97,9 +97,9 @@
       <BrowseInformation>true</BrowseInformation>
       <CompileAs>CompileAsC</CompileAs>
       <StringPooling>true</StringPooling>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <Optimization>Disabled</Optimization>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
     </ClCompile>
@@ -114,7 +114,7 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
     <ClCompile>
       <PrecompiledHeader>Use</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
@@ -128,9 +128,9 @@
       <BrowseInformation>true</BrowseInformation>
       <CompileAs>CompileAsC</CompileAs>
       <StringPooling>true</StringPooling>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
     </ClCompile>
     <Link>
@@ -140,7 +140,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <FunctionLevelLinking>true</FunctionLevelLinking>
@@ -153,9 +153,9 @@
       <CompileAs>CompileAsC</CompileAs>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <Optimization>Full</Optimization>
     </ClCompile>
     <Link>
@@ -170,7 +170,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>Use</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
@@ -184,9 +184,9 @@
       <CompileAs>CompileAsC</CompileAs>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <Optimization>Full</Optimization>
       <WholeProgramOptimization>true</WholeProgramOptimization>
     </ClCompile>
diff --git a/projects/vstudio/pnglibconf/pnglibconf.vcxproj b/projects/vstudio/pnglibconf/pnglibconf.vcxproj
index e2a232c..efcc440 100644
--- a/projects/vstudio/pnglibconf/pnglibconf.vcxproj
+++ b/projects/vstudio/pnglibconf/pnglibconf.vcxproj
@@ -30,7 +30,7 @@
   </PropertyGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <Optimization>MaxSpeed</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
diff --git a/projects/vstudio/pngstest/pngstest.vcxproj b/projects/vstudio/pngstest/pngstest.vcxproj
index 0d2980d..21810e3 100644
--- a/projects/vstudio/pngstest/pngstest.vcxproj
+++ b/projects/vstudio/pngstest/pngstest.vcxproj
@@ -76,16 +76,16 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <StringPooling>true</StringPooling>
       <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -109,7 +109,7 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
     <ClCompile>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
@@ -117,9 +117,9 @@
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <StringPooling>true</StringPooling>
       <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -141,7 +141,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
@@ -149,9 +149,9 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
       <BrowseInformation>true</BrowseInformation>
@@ -176,7 +176,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
@@ -185,9 +185,9 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
       <BrowseInformation>true</BrowseInformation>
diff --git a/projects/vstudio/pngtest/pngtest.vcxproj b/projects/vstudio/pngtest/pngtest.vcxproj
index bf9266f..f1df07d 100644
--- a/projects/vstudio/pngtest/pngtest.vcxproj
+++ b/projects/vstudio/pngtest/pngtest.vcxproj
@@ -76,16 +76,16 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <StringPooling>true</StringPooling>
       <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -109,7 +109,7 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
     <ClCompile>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
@@ -117,9 +117,9 @@
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <StringPooling>true</StringPooling>
       <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -141,7 +141,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
@@ -149,9 +149,9 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
       <BrowseInformation>true</BrowseInformation>
@@ -176,7 +176,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
@@ -185,9 +185,9 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
       <BrowseInformation>true</BrowseInformation>
diff --git a/projects/vstudio/pngunknown/pngunknown.vcxproj b/projects/vstudio/pngunknown/pngunknown.vcxproj
index a30cc7a..409d662 100644
--- a/projects/vstudio/pngunknown/pngunknown.vcxproj
+++ b/projects/vstudio/pngunknown/pngunknown.vcxproj
@@ -76,16 +76,16 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <StringPooling>true</StringPooling>
       <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -109,7 +109,7 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
     <ClCompile>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
@@ -117,9 +117,9 @@
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <StringPooling>true</StringPooling>
       <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -141,7 +141,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
@@ -149,9 +149,9 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
       <BrowseInformation>true</BrowseInformation>
@@ -176,7 +176,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
@@ -185,9 +185,9 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
       <BrowseInformation>true</BrowseInformation>
diff --git a/projects/vstudio/pngvalid/pngvalid.vcxproj b/projects/vstudio/pngvalid/pngvalid.vcxproj
index 07cf241..c117d29 100644
--- a/projects/vstudio/pngvalid/pngvalid.vcxproj
+++ b/projects/vstudio/pngvalid/pngvalid.vcxproj
@@ -76,16 +76,16 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <StringPooling>true</StringPooling>
       <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -109,7 +109,7 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug Library|Win32'">
     <ClCompile>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <MinimalRebuild>false</MinimalRebuild>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
@@ -117,9 +117,9 @@
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <StringPooling>true</StringPooling>
       <FunctionLevelLinking>false</FunctionLevelLinking>
@@ -141,7 +141,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
@@ -149,9 +149,9 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;PNG_USE_DLL;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
       <BrowseInformation>true</BrowseInformation>
@@ -176,7 +176,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
     <ClCompile>
-      <WarningLevel>Level4</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <PrecompiledHeader>NotUsing</PrecompiledHeader>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
@@ -185,9 +185,9 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>$(ZLibSrcDir);..\..\..\scripts;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <DisableSpecificWarnings>4996;4127</DisableSpecificWarnings>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings)</DisableSpecificWarnings>
       <CompileAsManaged>false</CompileAsManaged>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <StringPooling>true</StringPooling>
       <MinimalRebuild>false</MinimalRebuild>
       <BrowseInformation>true</BrowseInformation>
diff --git a/projects/vstudio/zlib.props b/projects/vstudio/zlib.props
index 98613cf..d7a0325 100644
--- a/projects/vstudio/zlib.props
+++ b/projects/vstudio/zlib.props
@@ -41,5 +41,18 @@
          test it:
      -->
     <WindowsSDKDesktopARMSupport>true</WindowsSDKDesktopARMSupport>
+
+    <!-- The following lines provide a global (solution level) control of the
+         warnings issued by the compiler, these are used in the individual
+         project files (*/*.vcxproj) with, for zlib, some extra disables.
+
+         Different versions of Visual Studio may require different settings,
+         these settings work with Visual Studio 2013.  Just set
+         TreatWarningAsError to false to check the build without failing on
+         errors.
+     -->
+   <WarningLevel>EnableAllWarnings</WarningLevel>
+   <TreatWarningAsError>true</TreatWarningAsError>
+   <DisableSpecificWarnings>4255;4668;4710;4711;4746;4820;4996</DisableSpecificWarnings>
   </PropertyGroup>
 </Project>
diff --git a/projects/vstudio/zlib/zlib.vcxproj b/projects/vstudio/zlib/zlib.vcxproj
index 6e5b94a..0df16db 100644
--- a/projects/vstudio/zlib/zlib.vcxproj
+++ b/projects/vstudio/zlib/zlib.vcxproj
@@ -88,11 +88,13 @@
     <ClCompile>
       <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
-      <WarningLevel>TurnOffAllWarnings</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
       <BrowseInformation>true</BrowseInformation>
       <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
     </ClCompile>
     <Link>
       <TargetMachine>MachineX86</TargetMachine>
@@ -103,11 +105,13 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <WarningLevel>TurnOffAllWarnings</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Disabled</Optimization>
       <BrowseInformation>true</BrowseInformation>
       <FunctionLevelLinking>true</FunctionLevelLinking>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
@@ -118,7 +122,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release Library|Win32'">
     <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
       <IntrinsicFunctions>true</IntrinsicFunctions>
@@ -126,7 +130,8 @@
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <BrowseInformation>true</BrowseInformation>
       <FunctionLevelLinking>true</FunctionLevelLinking>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
       <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
     </ClCompile>
@@ -141,7 +146,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
+      <WarningLevel>$(WarningLevel)</WarningLevel>
       <DebugInformationFormat>ProgramDatabase</DebugInformationFormat>
       <Optimization>Full</Optimization>
       <IntrinsicFunctions>true</IntrinsicFunctions>
@@ -149,7 +154,8 @@
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <BrowseInformation>true</BrowseInformation>
       <FunctionLevelLinking>true</FunctionLevelLinking>
-      <TreatWarningAsError>true</TreatWarningAsError>
+      <DisableSpecificWarnings>$(DisableSpecificWarnings);4127;4131;4242;4244</DisableSpecificWarnings>
+      <TreatWarningAsError>$(TreatWarningAsError)</TreatWarningAsError>
       <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;Z_SOLO;%(PreprocessorDefinitions)</PreprocessorDefinitions>
     </ClCompile>
     <Link>